Isolate by ultracentrifugation and characterize by electrophoresis the aqueous humor lipoproteins. Lipids will be characterized by chromatographic and chemical methods. Human aqueous humor cholesterol levels will be assayed by gas-liquid chromatography. Utilization of aqueous humor lipoproteins by rabbit and bovine lens as an exogenous source of lipid for fiber cell membrane synthesis will be investigated using in vitro incubation and labeled lipoprotein components. The balance between exogenous and de novo synthesis of both protein and lipid components of cell membranes will be investigated using appropriate radioactive precursors. The intraocular site of aqueous humor lipoprotein synthesis will be investigated by incubating selected, isolated intraocular tissues with radioactive precursors and isolating lipoprotein from the incubation medium. Lens membrane protein isolation and synthesis will be investigated by SDS-gel chromatography and radioactive precursors. Finally, the mechanism of triparanol cataractogenesis will be investigated with desmosterol-lipoprotein or triparanol in vitro incubation. The effect of desmosterol on de novo cholesterol synthesis will be investigated. In addition, the amount of desmosterol in the aqueous humor of triparanol-fed rats will be assayed.